Cecilia hides an invisibility suit in her bathroom and invites Adrian over for dinner and kills him by slitting his throat with a knife.

Does Cecilia prove Adrian is alive?

We're watching an Invisible Man movie, so we know the score. Most of the film sees Cecilia begging others to believe her. Adrian is alive. He's invisible.

Why did Cecilia run away from Adrian?

Adrian Griffin was a wealthy and brilliant scientist who previously dated Cecilia Kass. After Cecilia ran away from him due to his abusive behavior, Adrian faked his death and left part of his fortune to Cecilia, but found a way to turn himself invisible and began to spite her.